The prior art of quick-disconnect hose couplings includes a well-known design covered by U.S. Milspec-MIL-C- 4109 E (Oct. 1976), which is in widespread commercial use and provides a spring-loaded poppet valve in a female coupling half which is directly in-line with a male coupling half. An example of a spring-loaded poppet valve construction is given by U.S. Pat. No. 4,420,022 to Landry. One disadvantage of this design is that the poppet valve somewhat reduces fluid or air flow since it is located in the flow path.
Another problem with this design is that upon insertion of the male coupling half, an unsafe condition occurs as fluid or air flow is allowed prior to completion of the mechanical connection. Where compressed air or gas is used, for example, the premature flow connection is especially dangerous as the couplings may be blown apart from one another as they are being connected or disconnected. Recognition of the danger posed in this condition is evidenced by the U.S. safety standard published as OSHA 1926.302 (b-1), which calls for the use of "positive means" to secure the hose to a pneumatic power tool to prevent accidental disconnection.
Another type of hose coupling uses a ball valve or swivel valve construction enabling mechanical connection of the male coupling half while the valve is in a blocked position, thus separating the mechanical and flow connection stages. Examples of this type of construction are given by U.S. Pat. No. 4,662,396 to Avnon, and French Pat. Nos. 2.466.696, 2.068.039, 2.028.653 and 1.008.934. These patents disclose a mechanical connection which is provided by a pair of shoulders formed in the ball valve housing which restrain a collar on the male coupling half as the ball valve is moved approximately 45 degrees between positions. Because the collar is spaced apart from the ball valve pivot point, friction is generated over the arc of travel resulting in gradual wearout of the mechanical connection and shortening of the useful life.
The various hose coupling designs described above require costly forging and machining processes for producing the ball valve housing, which drives up the overall unit cost. In addition, unguided movement of the ball valve in the patent to Avnon and in French Pat. Nos. '039 and '696 can result in cases where the ball valve is turned inward and becomes inacessible.
Therefore, it would be desirable to provide a low cost hose coupling device which is easily manipulated for quick connect and disconnect and is designed to minimize wearout of mechanically interlocking parts.